1. Technical Field
The present invention relates to a power amplifier, and more particularly, to a power amplifier for time division multiple access having a circuit capable of calibrating timing.
2. Description of the Related Art
A power amplifier for time division multiple access is applied to a mobile communication terminal and a base station system that can implement two-way transmission by time division and secure transmission and reception separation so as to transmit signals at high speed.
The power amplifier for time division multiple access requires a technology of switching power-amplified RF signals so as to secure isolation at the time of the two-way transmission of the time division multiple access transmitting and receiving signals at high speed. As the related art, there is a technology of electrically connecting a plurality of single pole double throw (SPDT) switches to output terminals of a plurality of amplifiers.
Meanwhile, the power amplifier for time division multiple access requires a timing control so as to satisfy time division standards for each terminal and receives a timing control signal from a communication chip set so as to satisfy a transmission standard.
In order to receive the timing control signal, the power amplifier for time division multiple access needs to satisfy the transmission standard under the provided timing conditions, in particular, satisfy power vs time (PVT) to all the power control levels (hereinafter, referred to as “PCLs”) under the provided timing conditions. In order to satisfy the PVT, the PCL should not deviate from a time mask.
However, a case in which the power amplifier cannot satisfy the PVT items to all the PCLs according to a location setting of a power logic enable signal that is a reference signal has often occurred.
In particular, the case in which the power amplifier satisfies the PVT in a low PCL but becomes spec out in a high PCL has occurred and as a result, performance of the power amplifier for time division multiple access may be degraded.